Absolute Intensities of Characteristic Infra-Red Absorption Bands of Aliphatic Hydrocarbons

Abstract

Integrated intensities of the 2900, 1460, and 1370 cm−1 infra-red absorption bands have been measured for twelve aliphatic hydrocarbons. The results are interpreted on the basis that the hydrocarbon molecule behaves like a non-interacting mixture of [Complex chemical formula] structural groups. The unit structural group intensities are 4.41×10−7, 3.81×10−7, and 1.39×10−7 cm2/(molecule second) for the CH3, CH2 and CH groups respectively in the 2900 cm−1 band; 0.544×10−7 and 0.232×10−7 for the CH3 and CH2 groups in the 1460 cm−1 band; and 0.394×10−7 for the CH3 group in the 1370 cm−1 band. Values calculated for the CH bond dipole moment divided by the equilibrium CH bond length vary from approximately 0.2×10−18 to 0.4×10−18 c.g.s. units. Values of approximately −0.75×10−10 are obtained for the change in CH bond dipole moment with change in CH bond length.

Micro-emulsion co-polymerisation of butyl acrylate with acrylic acid as binder for textile pigment printing

“…The stretching absorption of CZO (of carboxylic group) at 1,220 cm 2 1 and that of CZO (of ester group) 1,160 cm 2 1 were appeared in the FTIR spectrum of the prepared co-polymer ( Figure 5). Moreover, the absorption bands at 1,400 and 1,450 cm 2 1 give rise to CH 2 and CH 3 groups due to CZH bending vibrations present and this was in accordance with that reported by Francis (1950) and Torkington and Thompson (1945). These results show that the co-polymerisation process took place between acrylic acid and BA as shown in Figure 6 and the active carboxylic group remains unaffected during polymerisation process.…”

Infrared spectra of high polymers

“…Again, however, we have made the simplest assumptions about the transition moment directions, and these may not be correct. The ~ (CH2) (A) mode is not identified, but since the ~ (CHz) modes are much weaker than the b~ (CH3) modes [FRANCIS (57)] it is possible that b (CH~) (A) is overlapped by the stronger ~a(CH3) bands. The very strong a band at 1378 cm -1 is undoubtedly the 68 (CHs) (E) mode.…”

Integrated Intensities of Absorption Bands in Infrared Spectroscopy

“…The sum of the observed intensities in the 2900-cm" 1 region (his values were subdivided into symmetric and asymmetric methyl and methylene modes by arbitrary curve division) were not very different from values reported in solution [19,79], the differences being about 10 to 15% lower in the solid phase.…”

“…The discrepancies between the two sets of data from different investigators are due in part to the use of different sets of hydrocarbons, in part to differences in averaging, and in part to difference in background assumptions. Areas in one case were measured directly with an electronic integrator [79], in the other case with a planimeter [19]. [19].…”